JPS60240335A - Starting method of furnace coiler in steckel mill - Google Patents

Abstract

PURPOSE:To improve the quality and working efficiency by determining automatically an optimum driving pattern of a coiler with respect to the initial rate of slack of a strip which fluctuates with various parameters and setting the same to a driving device. CONSTITUTION:The delivery speed VM of the strip is detected by a speed detecting means and the passage of the front end of the strip through said position is detected by a strip detecting means provided on the upper stream side thereof. The coiler is started after the time t0 which satisfies the equation I upon passage of the strip. The coiler is accelerated up to the number NF of revolution calculated by the equation II. In the equation I, L1; the distance from the position where the passage of the front end of the strip is detected to the initial position of the slit port, alpha: the learning value of the length of the front end of the strip. In the equation II, D: the coiler diameter, L0; the learning value of the initial slack length of the strip, LL the displacement of the linear distance between pinch rolls and the slit port when the coiler rotates from the initial position to the position where the strip contacts with the circumferential surface of the coiler drum.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for starting a furnace coiler in a metal strip reversible hot rolling installation (hereinafter referred to as a Steckel mill) having furnace coilers before and after the rolling mill.

FIG. 1 is a side view schematically showing the configuration of a Steckel mill. The stake mill is a metal mill) IJ tube 1'f: rolling means consisting of upper and lower work rolls 2.2' for rolling and upper and lower banked rolls 3.3' for holding those work rolls with strong pressure. and a winding machine 4 called a furnace coiler provided before and after the rolling means. When rolling in a Steckel mill, the strip unwound from one filler is rolled by a work roll and then wound onto the other coiler. In this case, the strip is unwound in its entirety from one coiler, the end of which is also rolled, and then the strip is wound up by the other coiler (((). The strip is rolled from its tip and wound around the one coiler.In this way, the strip is rolled for a number of passes (an odd number of passes, usually 7 or 10 passes) while reversing the conveying direction to obtain a product with the desired thickness. If the strip is repeatedly rolled, the salinity of the strip becomes such that it cannot be rolled down, so a furnace 5 is provided surrounding the coiler 4 to heat the coiled strip in order to prevent the temperature from dropping. .

A problem in operating a Stetskell mill is to fit the tip of the strip into the slit of the coiler drum. FIG. 2 is a side view for explaining this work. The rolled strip advances along a table (not shown) (in the example shown from left to right as indicated by the arrow) and passes through the nip of the pinch rolls 8.8' before passing through the previously raised guide table B. The leading end 1' of the strip is guided to be inserted into the slit 4' of the drum of the coiler 4 which is stopped. When the leading end 1' of the strip is inserted into the slit 4' by a predetermined length, the coiler is activated to start winding the strip, and the guide table 6 is moved to the second position.
Figure (() is lowered to the retracted position indicated by the dotted line. Initially, there is slack in the strip, so the winding speed of the coiler is accelerated by a speed ζ faster than the rolling speed of the strip, and after eliminating the slack in the strip, the ) l) Winding is performed with a certain tension applied to the tube.

In such a coiler startup operation 1fC, (1)
(2) The coiler is rotated at a speed higher than the rolling speed of the strip to reduce the slack in the strip. (3) Once the slack in the strip has been removed, properly perform the work to avoid applying shock to the strip and at the same time synchronize the winding speed of the rc coiler with the rolling speed of the strip. That is essential.

If the feeding length of the strip at the time of completion of startup is substantially smaller than the winding length TJF of the strip by the coiler, the tip of the strip will be squeezed and unraveled before tension is applied (necking occurs).

Furthermore, if the LM is substantially thicker than the width, the initial slack of the strip remains, resulting in the inconvenience that the strip hits the furnace and gets scratched, or that the strip is struck immediately after tension is applied and the tip is squeezed. It happens. It would be ideal if the coiler could be started up and operated so that Lp -Ly, but it is extremely difficult in practice.

In the case of special steel, especially stainless steel strip, the finishing temperature differs depending on the steel type, and the number of rolling passes also varies depending on the finished plate thickness, resulting in a variation in the temperature drop rate at the strip tip. The initial sagging length of the strip varies. In other words, the slack length of the strip changes due to the difference in the traveling position of the strip between when the coiler starts and when the coiler finishes starting.

Conventionally, when starting a coiler, the initial slack length of the strip was determined by the operator based on experience each time. The coiler speed pattern was set based on the strip speed VM and by carefully adjusting the startup timing using a timer while observing the startup process.

However, the problem with such starting methods is that the speed pattern of the coiler does not correspond to the initial sag length of the strip that actually occurs, and so failure to start often causes the strip tip to become cold. This causes deformation such as upward curvature, and it enters the slit of the coiler, making winding even more difficult. In addition, the conventional coiler starting method relies heavily on the intuition of the operator, and the efficiency of rolling and the quality of the product depend on the skill level of the operator. In addition, adjusting the timer for each rolling pass complicates the work.

An object of the present invention is to provide a method for starting a furnace coiler in a Steckel mill that can solve the above-mentioned problems of the conventional method and meet the demands for improved quality and work efficiency.

The method of the present invention for achieving the above object is such that when finish rolling a metal strip in a reversible hot rolling equipment having furnace coilers before and after the rolling means, the tip of the strip rolled by the rolling means passes through pinch rolls. Immediately after the required length is inserted into the slit of the drum of the stopped furnace coiler, the coiler is started, its rotational circumferential speed is accelerated by a predetermined time constant T, and after a certain period of time, a predetermined In the method of starting the coiler with a speed pattern that decelerates with a time constant of 12 to match the strip delivery speed, the speed detection means detects the strip delivery speed vM, and the coiler is upstream of the slit in the running direction of the strip. (located on the side)
l) The passage of the tip of the strip at the relevant position is detected by the knob position detection means, and after the tip of the strip passes the position, formula (1) is calculated from the passing detection position of the strip tip to the initial position of the slit opening. is the distance, and α
is the learned value of the length of the tip of the strip inserted into the slit). After that, start the coiler (2)
) (In the formula, D is the diameter of the coiler, Lo is the learned value of the initial slack length of the strip υ, and LL is the rotation of the coiler from the initial position to position 1, where the strip touches the coiler drum circumference. θ is the amount of angular displacement of the coiler when the coiler rotates from the initial position until the strip touches the circumference of the coiler drum. , and T, , 'r2 and ■yu have the meanings described above), or the speed is accelerated to the rotation speed NF calculated by T, , 'r2 and ■yu have the meanings described above), or the above N is the rated rotation speed of the drive motor of the coiler. If N□ is exceeded, accelerate the coiler to the rated rotation speed N□ of its drive motor, and use the formula (3)% formula % at the rated rotation speed 1 sun 8 (where D is the diameter of the coiler). Lo is the learned value of the initial slack length of the strip, and Lo is the learning value between the pinch roll and the slit opening when the coiler rotates from the initial position to a position where the strip touches the coilard's 2mm circumference. θ is the amount of displacement in the straight line distance, θ is the angular displacement of the coiler when the coiler rotates from the initial position to a position where the strip touches the coilard's 2mm circumference, and VFR is the amount of displacement of the coiler at the rated rotation speed. The peripheral speed of rotation is πDN, , □, t4 is the time from the start of coiler activation to the completion of activation, and T1,
It is characterized in that the rated rotational drive is continued for the time t calculated by T2 and (8) having the above-mentioned meanings, and then decelerated.

Referring to FIG. 2, strip 1 is placed on work roll 2.
2', passed through pinch rolls 8.8', and guided by the guide table 6 in the raised position, the tip 1' is inserted into the slit 4' of the stationary furnace coiler 4. In the method of the present invention, in the running direction 1 of the strip (with respect to the strip nog position detecting means 7 provided at a position upstream of the slit 4', passage of the strip tip 1' through the relevant position is detected, and the slit at that time) IJ speed V, speed detection means (not shown)
Detected by. Speed detection means is pinch roll 8.8
It is convenient to attach it to one of the After the strip tip 1' passes the position of the position detection means 7, the coiler ~ is determined by the formula (1) % formula % (in the formula, L1 is S). Dust is measured at the distance from the passing detection position of the IJ knob tip to the initial position of the slit opening. , and α is the learned value of the length of the tip of the strip inserted into the slit). will be launched later.

After start-up, the coiler is accelerated by a predetermined time constant T1, and after a certain time, is decelerated by a predetermined time constant T2 until the circumferential speed matches the IJ tube speed, and the strip is tension-controlled. This completes the start-up of the coiler, and thereafter the coiler is operated steadily at a circumferential speed equal to the stripping speed. The acceleration time constant T1 and the deceleration time constant T2 are predetermined by experience. Figures 5-a and 5-b show typical velocity patterns of the coiler during start-up. The vertical axis shows the rotational speed N of the coiler, and the horizontal axis shows the elapsed time t after the strip tip 1' passes the position of the detection means 7. With the speed pattern shown in Figure 5-a, the coiler moves at time t. It is activated by the smell, and is accelerated at the rotation speed NF[t with a time constant T1 until time 1 s, and at a time t4.
Until then, the rotational speed is reduced to a rotational speed corresponding to the stripping speed with a time constant T2, and thereafter the rotational speed is driven at a rotational speed corresponding to the stripping speed. According to the speed pattern shown in Figure 3-b, the coiler moves at time t. VC, is accelerated at the rated rotation speed NFRIc-i of the drive motor of the coiler with an opening time constant T1 until time t3, is driven at its rated rotation speed Nl1R until time ti, and is driven at the rated rotation speed Nl1R until time t.
With the opening time constant T2 in the four-way mode, the rotational speed is reduced to a rotational speed corresponding to the stripping speed, and thereafter, the rotational speed is driven at a rotational speed corresponding to the stripping speed. For either speed pattern, the initial sag length of the strip at time j4t. It is important to determine the NF or tF so that it can be absorbed without excess or deficiency.

FIG. 4 shows the relative positions when the device is modeled.

In the figure, P is the infinitely small diameter of the pinch roll, Pl is the driving fulcrum of the guide table, P2 is the position directly below the center O of the coiler, E is the position of the slit opening when the coiler is in the initial position, and F is the position of the slit opening when the coiler is in the initial position. The fulcrum of the straight line connecting points P and 0 with the drum circumference, G1 and G2 are the positions of the contact points when the coiler wraps around the strip and the strip touches the coiler circumference, and H connects the points P2 and 0. The points of intersection between the straight line and the drum circumference are shown. However, -d, bracket -b, P
2H-a, sweat-e, 靜-4, △KOF-θ0 (called Coiler's timing angle) and ZG, OF = Z()20F
-θ5 is the length that the strip moves while the free end of the strip fixed on the coiler circumference moves from E to G1 or G2, i.e. the distance from the initial position of the coiler until the strip touches the coiler drum circumference. The amount of displacement LL in the straight line distance between the pinch roll and the slit opening when rotated to the desired position is expressed as follows: LL=PG-.

Meanwhile, the initial slack length of the strip. The method of the present invention performs learning control of this point, but if there is no learned value, a value calculated from Lo-(d1E piece)-Madashi) may be used.

Assume the speed pattern after starting the coiler shown in Figure 5-a. The time required for the coiler to rotate from the initial position to the position where the strip touches the circumference of the coiler drum is tL, and the angular position of the coiler during that time is θ.
However, when the coiler is rotated clockwise in FIG. 4, θ=05-0. , θ-θ when the coiler is rotated counterclockwise in FIG. Ten.

After a time tL the strip wraps around the coiler. Therefore, the length L of the strip wound by the coiler by time t4
12 is ■ -πDN initial sagging of the strip due to the rotation of the coiler at time t, 1; In order to absorb vMt40Lo=LL
10LB must be established.

When this formula is rearranged with respect to VFIC, it becomes. Solving this quadratic equation for VFI/C and dividing the obtained V by πD to find N yields (2).

Thus, in the method of the present invention, the time t after the strip tip passes the position detection means 7 according to equation (1). After that, the coiler is started, and thereafter the coiler is accelerated and decelerated at a predetermined time constant to absorb the initial slack length of the strip. to drive.

If the speed calculated by equation (2) exceeds the rated rotational speed NFR of the coiler drive motor, the speed pattern shown in FIG. 5-b is used. In this case, LB −”p, Rj23”” ti+v,, (t3'
-T, )2T, 2T.

14 (t4 to)"+Vy (to t3)T2 2θT1 VFR=π""n't1+"" 66ON1., R Substituting this L8 into vMt, + Lo= LLLL11 and rearranging it gives the following.

The initial sag length of the strip for any type of velocity pattern. , the time constants T1 and T2, and the length α of the tip of the strip inserted into the slit are controlled by learning. These controls are preferably performed as follows. In other words, after experiencing coiler startup operation,
The coiler winding peripheral speed VF is made equal to the strip feed speed VM [The strip length LF actually wound by the coiler at a certain point after completion of startup is calculated by integrating the rotation speed of the coiler, and this Calculate the difference ΔL between LF and the fed strip length LM calculated by integrating the actually detected strip speed vMt. Then, the average value of multiple LL values obtained from the experience of starting operation under the same conditions (same steel type, heating temperature, width, thickness, and number of rolling passes) is added (including subtraction) to Lo. This is prepared as a learned value of the initial slack length of the strip that can be adopted in the next start-up operation under the same conditions. Additionally, the product of the experienced LL multiplied by the appropriate constant p is added to either T or T2 (including subtraction).
Then, prepare the obtained value as a learned time constant value that can be used in the next startup operation under the same conditions.

Furthermore, LL multiplied by an appropriate constant q is added to α (including subtraction), and the obtained value is used to learn the length of the tip of the strip to be inserted into the slit, which can be adopted in the next start-up operation under the same conditions. Prepare as a value.

FIG. 5 is a flowchart for explaining the steps of an example of the furnace coiler starting method according to the present invention. In the illustrated system, a starting command is output to the coiler drive motor through arithmetic processing by a microcomputer (1).

First, the steel type, width, thickness, and other parameters of the strip are input into the setting device A. Then, read the initial slack length of the strip from the reading program BIC. , time constants T1, T2 are derived from table D. At this time,
Physical constants (r, c and θL in FIG. 4) are read from table E by CVc. Next, when the strip tip passes the position detection means 7, the program F begins to integrate the velocity vM.

On the other hand, the reading program G determines the timing angle displacement θ of the coiler slit. is converted by a converter engineer and inputted from an angle detector (3) installed on the drive shaft of the coiler. Program J starts the above L from the value read above.
Calculate L. From Lo, LL, vM, T, and T2, the maximum rotation speed NF of the coiler required to eliminate the amount of slack in the strip is calculated by program K. 5th-
Figure a shows the speed pattern of the coiler thus obtained. Next, the determination program L determines whether the value integrated by the program F matches -α. If they match, a pattern for accelerating the coiler until it reaches the rotational speed NFVC calculated in the program is outputted to the accelerator 4 by the output program Ml/C, and the coiler is activated. If they do not match, the calculations after the strip velocity integral calculation using FK are repeated until they match.

After starting the coiler with the circumferential speed matching the stripping speed, the length LF of the strip actually wound by the coiler is determined by the angle detector (3) through the converter program N.
and read the actual strip speed through the speed detection means 1.2) and the converter H;
By integrating this from the start of activation of the coiler, the length of the fed strip is calculated from the T-+Mk program OVc, and the fan is subtracted from LF using the subtraction program PK to calculate the difference ΔL. This difference ΔL is stored in a data table S for each steel type, width, thickness, and number of passes.

Then, the average of multiple △L values experienced for the steel type, width, thickness, and number of rolling passes is added to Lo (
(including subtraction) is calculated by program R,
The obtained value is stored in table D as a learned value of the initial slack length that can be adopted in the next startup operation under the same conditions. Also, add (subtract) △L multiplied by an appropriate constant p to one of the time constants T1 and T2, and use the obtained value as a learning value of the time constant that can be adopted in the next startup operation under the same conditions. can be stored in table D as follows. Furthermore, △LKL multiplied by a certain constant q is added (subtracted) to α, and the obtained value is used as the learned value of the length of the tip of the strip inserted into the slit that can be adopted in the next startup operation under the same conditions. Table DK can be stored.

In addition, if the rotation speed NF exceeds the rated rotation speed NFR of the coiler drive motor, the operating time 1F can be set to N instead of the NF calculation program K. Figure 5-b shows the coiler speed pattern in such a case.

According to the method of the present invention, when starting up a furnace coiler in a Stetskell mill, the optimum drive pattern for the coiler is automatically determined based on the initial slack amount of the strut, which varies depending on various types of slugs. The initial slack of the strip can be quickly absorbed without manual adjustment and setting. Therefore, the production of hot-rolled holes, necking, and off-gauge products at the leading and trailing ends of the strip is reduced, and the yield and quality of products can be improved, and the labor of production personnel can be saved.

[Brief explanation of the drawing]

Figure 1 is a side view showing the general structure of the Stetskel mill, Figure 2
The figure shows a side view illustrating the operation of inserting the tip of the strip into the slit of the coiler tram, Figures 3-a and 3-b show typical speed patterns when starting the coiler, and Figure 4 A diagram showing the relative positions when the device is modeled, and FIG. 5 is a flowchart explaining the procedure of the method of the present invention. 1...Strip, 1'...Strip tip, 2,
2'...work roll, 3.3'...bank up roll, 4...coiler, 4'...coiler slit,
5...Fuboosu, 6...Guide table, 7.
...Position detection means, 8, 8'...Pinch roll, (1
)... Microcomputer-1 (2)... Speed detection means, (3)... Angle detector, (4)... Accelerator, A
...Setting device, B...Reading program, C...Reading program, D...Data table, E...
・Take table, F... Integrator, G... Loading program, Engineering (... Converter, Engineering... Converter, J
...LL calculation program, K...NF calculation program, L...judgment program, M...speed pattern output program, N...reading program, 0...
Inciting calculation program, P... Subtraction program, R...
Arithmetic program, S...data table. Applicant: Nisshin Steel Co., Ltd. 1st drawing, 2nd drawing, 3-a, 3-b to', tLt, t'3t. Procedural amendment 1982 Patent Application No. 95136 2, Title of invention Relationship to the Furnace Coiler Case in Stetzkel Mill Representative of patent applicant Yuzuru Abe 4, Agent No. 162 7, Subject of amendment (1) Details of the invention The explanation has been amended as follows. (a) The formula is corrected to the formula on page 21, line 2 of the specification. 1) Correct the formula on page 23, lines 8-9 of the specification.

Claims (1)

[Claims] (1) Before and after the rolling mill (when the metal strip is finish rolled in a reversible hot rolling facility equipped with a furnace coiler, the tip of the IJ tube is rolled by a pinch roll) Immediately after the required length is inserted into the slit of the drum of the stopped furnace coiler through The time constant “number T”
A method of starting the coiler with a speed pattern that decelerates in step 2 to match the strip delivery speed (in step C, detects the strip delivery speed vM by the speed detection means and step).IJ tube running direction (C) Regarding this, passage of the strip tip at the relevant position is detected by a strip position detection means provided at a position upstream of the slit, and after the strip tip passes the relevant position, the formula t11 L, 10, a = ftovMat (1) (formula Medium L
(1 is the distance from the passing detection position of the strip tip to the initial position of the slit, and α is the learned value of the length of the strip tip inserted into the slit). After the foil coiler is started and the coiler is moved to the initial position using equation 12, where D is the coiler diameter and Lo is the learned value of the initial sagging length of the strip. θ is the amount of displacement in the straight line distance between the pinch roll and the strip when the strip rotates from the initial position to the position where the strip touches the coiler drum circumference (C). This is the angular position of the coiler when the coiler rotates to the position where it reaches , and T1, T2 and vM have the meanings described above). The starting method. (2+ Integrating the rotational speed of the coiler with the strip length LF actually wound by the coiler at a certain point after the completion of starting when the strip winding circumferential speed of the coiler is made equal to the strip feeding speed. This L
2 and the fed strip length calculated by integrating the actually detected strip speed VM k, and then calculate the average value of the plurality of LL values determined by the startup operation so far. . 2. The method according to claim 1, wherein the value obtained by adding K is prepared as a learned value of the initial slack length of the strip that can be adopted in the next start-up operation. (3) The strip length LF actually wound by the coiler at a certain point after the start-up is completed when the strip winding speed of the coiler is made to match the strip feeding speed is calculated by integrating the rotation speed of the coiler. , and the actually detected strip speed vM1, calculated by integrating the actual detected strip speed vM1), and the IJ knob length LM. According to claim 1 or 2, the method is added to one of the time constants T1 and T2, and the obtained value is prepared as a learning value of the time constant that can be adopted in the next startup operation. For those who write: (4) Integrate the length of the strip actually wound by the coiler at a certain point after startup is completed when the coiler's strip winding circumferential speed matches the strip feeding speed with the rotational speed of the coiler. Calculated by, and L
Calculated by integrating F and the actually detected strip speed vM, and then ? and the fed strip length LM calculated by integrating the actually detected strip speed vM: Calculate the difference △L'f: and calculate the difference △
Any one of claims 1 to 3, characterized in that the value obtained by multiplying the LIC by an appropriate constant q is prepared as a learned value of the length of the tip of the strip to be inserted into the slit that can be adopted in the next start-up operation. The method described in Section 1. (5) Metal rolling equipment with reversible hot rolling equipment that has furnace coilers before and after the rolling means) When finish rolling an IJ tube, the tip of the strip rolled by the rolling means is stopped after passing through pinch rolls. Immediately after the required length of the coiler is inserted into the slit of the drum of the furnace coiler, the coiler is started and its rotational circumferential speed is accelerated by a predetermined time constant T.
2, the coiler is started with a speed pattern that decelerates and matches the strip delivery speed (in this method, the speed detection means detects the strip delivery speed vM, and the speed is lower than that of the slit in the running direction of the strip). The strip tip position detection means provided at the upstream position [, 1: Tsutes] detects the passage of the IJ knob tip at the relevant position, and after the strip tip passes the relevant position, formula (1) % formula % (1) ( In the formula, L1 is the distance from the passing detection position of the strip tip to the initial position of the slit opening, and α is the learned value of the length of the strip tip inserted into the slit. Later, the coiler is started to start, and the coiler is operated at the rated rotational speed NFR of its drive motor according to the formula (3) (where D is the diameter of the coiler and Lo is the learned value of the initial slack length of the strip. LL is the displacement of the linear distance between the pinch roll and the slit opening when the coiler rotates from the initial position to the position where the strip touches the coiler drum, and θ is the displacement amount of the linear distance between the coiler and the strip from the initial position. Coil 2 - Angular displacement of the coiler when it rotates to a position where it touches the drum circumference. FR is the rotational circumferential speed of the coiler at the rated rotation speed, i.e. πJ) NFR, and t4 is the start-up of the coiler. It is the time from start to completion of startup, and T1, T
2 and (2) have the above-mentioned meanings) The method described above is characterized in that the rated rotational drive is continued for a time 1F calculated as follows, and then decelerated. (6) Calculate the strip length LF actually wound by the coiler at a certain point after the start-up is completed by making the strip winding speed of the coiler match the strip feeding speed by integrating the rotational speed of the coiler, This LF
Calculate the difference between the fed strip length LM calculated by integrating the actually detected strip speed 9, and calculate the average value of multiple △L values determined by the startup operation so far. iL. 6. The method according to claim 5, wherein the sum of the initial sagging length of the strip is prepared as a learning value of the initial slack length of the strip that can be adopted in the next start-up operation. (7) Calculate the strip length LF actually wound by the coiler at a certain point after the start-up is completed by making the coiler's strip winding circumferential speed match the strip feed-shrinking speed by integrating the rotational speed of the coiler. , L3 with
and the fed strip length Lヮ calculated by integrating the actually detected strip speed vM △
Find L, then multiply △LK by an appropriate constant p and add it to either time constant T1 or T2, and prepare the obtained value as a learning value of the time constant that can be adopted in the next startup operation. A method according to claim 5 or 6, characterized in that: (8) Calculate the strip length LF actually wound by the coiler at a certain point after the start-up is completed by making the coiler's strip winding peripheral speed match the strip feeding speed by integrating the rotation speed of the coiler, and calculate this by integrating the rotational speed of the coiler. L
Calculate the difference △L between F and the fed strip length LM calculated by integrating the actually detected strip speed vM, and then multiply that △L by an appropriate constant q for the next start-up operation. 8. The method according to any one of claims 5 to 7, characterized in that a learned value is prepared for the length of the tip of the strip or lip to be inserted into the slit that can be adopted.